In the past, there has been proposed a light emitting device with a structure shown in FIG. 27 as a light emitting device required to emit white light (JP 2007-109701 A: patent document 1). This light emitting device includes a metal plate 203 having functions of heat dissipation and light reflection, a wiring board 201 including a through hole 207 allowing passage of light, and a bonding sheet 202 bonding the wiring board 201 and the metal plate 203. Further, in this light emitting device, a light emitting element 214 constituted by an LED chip is mounted on a part of the metal plate 203 exposed via the through hole 207 of the wiring board 201, and the light emitting element 214 is bonded to a land 206 on an upper surface of the wiring board 201 in a wire bonding manner by use of metal wires 215.
It is disclosed that the metal plate 203 of the aforementioned light emitting device may be an aluminum plate.
With regard to the light emitting device with the structure shown in FIG. 27, it is considered that some of rays of light emitted from the light emitting layer of the light emitting element 214 pass through the light emitting element 214 and then are reflected by the metal plate 203. However, regarding this light emitting device, it is considered that the light-outcoupling efficiency tends to decrease due to absorption and/or multiple reflection of rays of light totally reflected by the metal plate 203 in the light emitting element 214.